RX-100 Sharpness in Portrait Mode.

New RX-100 owner, been playing around with it and taking some pictures. One weird quirk I noticed that I can't explain is that my pictures keep coming out sharper in Portrait mode than Av or M, even if I use the exact same exposure settings the camera chose in Portrait mode.

For example, I took a couple of portraits today at ISO 100, f/4, 1/250. Good settings for sharpness imo. In Portrait mode at that exposure, my subject was WICKED sharp. Basically the sharpness is on par with anything I've seen from my Canon FF DSLR.

If I mimic that exposure and set the camera to M , or similar exposure at Av, the pictures are still pretty good (not soft), but noticeably softer than in Portrait Mode.

Anyone else notice this from their cameras, and any idea what could be causing it? I generally like to shoot in M or Av, so I want to get the maximum sharpness possible in those settings. I shoot in RAW.